Ligand‐Engineering MoS ₂ ‐Osmium Heterostructure as Highly Active and Specific Peroxidase‐Mimic Nanozyme for Interference‐Free and Multimode Biosensing

Abstract It is still a challenge to fabricate nanozymes with both of high catalytic activity and specificity. Herein, a ligand engineering method is developed to fabricate osmium (Os) nanocluster‐Molybdenum disulfide (MoS ₂ ) heterostructure with superior peroxidase‐specific activity. It has been verified that polyvinylpyrrolidone (PVP) as ligands can confine amorphous Os nanoclusters growing on the MoS ₂ nanosheet, mechanism studies indicated that PVP acts as appropriate size‐limiting reagent and electronic transmission bridge between of Os and MoS ₂ which can synergistically improve the peroxidase‐specific activity. Moreover, the ligand engineering will not affect the peroxidase‐mimic specificity of MoS ₂ ‐Os. Further, it is found that MoS ₂ ‐Os possessed superior photothermal conversion efficiency, therefore, MoS ₂ ‐Os can be used as colorimetric and photothermal dual‐mode tags. MoS ₂ ‐Os combined lateral flow strip is established for breast cancer HER2 ⁺ exosomes colorimetric and photothermal detection with superior sensitivity and broader liner range, MoS ₂ ‐Os based interference‐free salivary glucose biosensor is also established with a LOD of 0.1 µM, almost 100‐fold sensitivity than that of Glucose Assay Kit. Therefore, this work developed a ligand‐engineering strategy to regulate Os nanocluster on MoS ₂ and improve the peroxidase‐specific activity, the multifunctional MoS ₂ ‐Os nanozyme can be used for accurate and multimode biosensing in varies scenes.